Incendiary



nited gestes Fatent O i INCENDIARY James C. Loftin, United States Army, and Leo Finkelstein, Aberdeen, and Edward M. Wharton, Edgewood, Md., assignors to the United States of America as represented by the Secretary of War, as trustee Application February 12, 1944, Serial No. 522,082

3 Claims. (Cl. IGZ- 6) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government, for governmental' purposes, without the payment to us of any royalty there- This invention relates generally to toxic incendiary munitions, and has particular relation to toxic incendiary bombs adapted to be dropped from aircraft, which give off fumes of cadmium oxide upon burning.

It has been established that fumes of burning cadmium, i. e. cadmium oxide, are exceedingly toxic. Accordingly, the primary object of this invention is the provision of an incendiary munition which upon functioning sets up a toxic cadmium oxide aerosol.

Another object of this invention is the provision of a toxic incendiary bomb adapted to be dropped from aircraft which is both highly toxic and highly incendiary in action.

Other objects of the invention will, in part, be obvious, and will, in part, appear hereinafter.

For a more complete understanding of the nature and scope of this invention, reference may be had to the following detailed description thereof taken in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal sectional view of one type of toxic incendiary bomb having a magnesium-cadmium alloy body;

Figure 2 is a vertical sectional view taken on line 2- of Figure 1;

Figure 3 is a vertical sectional View taken on line 3--3 of Figure 1;

Figure 4 is a longitudinal sectional view of a modified form of toxic incendiary bomb having a steel casing with' cadmium-Thermit charge;

Figure 5 is a vertical sectional view taken on line 5--5 of Figure 4;

vFigure 6 is a vertical sectional view taken on line 6--6 of Figure 4; and

Figure 7 is an elevational View of a deformable crossshapedpmember for retaining the firing pin of the bomb ofFigure 1 in position until impact.

vReferring particularly to Figure 1 of the drawings, a toxic incendiary bomb is indicated generally at 5 which formsone embodiment of this invention. The bomb 5 comprises a cast magnesium-cadmium alloy hexagonally shaped body 6 which istilled with a Thermit-type charge 7.- VA cast'iron nose 8 is provided at the left hand end of the bomb 5 in Figure l which serves to keep the bomb upright when dropped from aircraft.

' A rst tire'- charge is loaded against the right hand end r 2,824,515 Patented Feb. .25, 1958"' ice The igniter l5 is adapted to be set olf or tired by a tiring pin 18 contained in a tiring pin holder 19. The tiring-v pin 18 may be made of aluminum or steel and consists, of a weight portion 21 with a pin 22. The tiring pin has a reduced diameter portion 23 formed on the right hand or upper end thereof which is adapted to fit within an inturned flange 24 of the tiring pin holder 19. The firing pin 18 is normally retained in the position shown by means of a screw 25l and a cross-shaped brass member 26 (Figure 7). The cross-shaped member 26 is made of brass or other deformable material so that upon a prede` termined impact of the bomb 5, the arms will fold up and permit the tiring pin 18 to move downward.

The tiring pin assembly is held in place by three screws` 30 as shown in Figure 3. A safety pin 31 is provided" for preventing the movement of the tiring pin 18. The safety pin 31 is provided with a compressed spring 32 fitting there-around which tends to force the safety pin 31 to the released or withdrawn position as shown in Figures 1 and 3. The particular type of bomb 5 shownin Figure l is adapted to be loaded' into an aircraft in clusters so that a number of bombs, for example, 50 or more, lit against each other so as to hold the safety pins 31 in the safety position. A

A hexagonally shaped tail 35 of sheet steel is fittedv over the right hand or upper end of the body 6 as shown in Figure 1, and is held in place thereon by the three screws 30 as shown in Figure 3. The tail 35 stabilizes the downward liight of the bomb 5.

As shown in Figures l and 2, three vent holes or openings 33 are formed in the casting 6 between the primer cap 15 and the first tire charge 9. The outer ends of the vents 33 are counterbored so as to receive the plugs or` Stoppers 34 which may be made of rubber, fiber board' or metal cups. In order to make the bomb 5 waterproof, the outside surfaces of the plugs 34 are coated with a waterproof cement or laquer. Preferably, the inner counterbored surfaces of the vent holes 33 are also lacquered before the insertion of the plugs 34. l

One specific form of the bomb 5 which has been exhaustively tested and standardized forprocurement and use has a total weight of about 4 lbs. and an over-all length of about 2111/32 inches. In this particular bomb, magnesium-cadmium casting 6 has a Weight of about 1.4 lbs. and a length of about 111/2 inches. For the greater part of its length the casting 6 has a thickness of about i 1%2 of an inch. The body 6 may contain as low as 4% cadmium,.but preferably it has the following composition:

Aluminum 5.5 to 6.3%. Cadmium k19.0 to 22.5%. Zinc v not over 1.5%. Manganese 0.1 to 1.0%. Impurities-; s Less than 0.5%. Magnesium Remainder.

of the Thermit charge 7 as shown in Figure l. The first i lire charge 9 is provided with a truncated conical projection 10 adapted to be fitted into a correspondingly shaped recess in the end of the Thermit charge 7. VA de. pression 11 is formed in the center of the exposed sur'- face of the first iire charge 9 which has been found to improve the ignition thereof. g The first tire charge 9 is adapted to be ignited by a primercap or detonator 15 spaced therefrom and held in aprimer cap holder 16 of steel or aluminum which tits against the shoulder 17 formediin ,the casting 6. 1

One lot of magnesium-cadmium bodies which proved to i be very satisfactory had the following composition:

Aluminum` 6.3%.l Cadmium 22.5%. Zincy l I Y Less than` 0.1%'.- Manganese 0.22%'. Magnesium 71.4%.

A Thermit-type charge 7 which has been yfound to be' very satisfactory hasthe following composition in; per-- centage-by weight:A Y-

Aluminum, granular p p 5 1- approximately equal incrementsjunder` adead'load pres- Y sure of 6,000to 7,000 lbs-usinga'ram yshaped to form a truncated conical depression corresponding to'the shape of the truncated projection 10 of theV first recharge 9.

The first fire charge 9 for a 25gram'Thermitcharge 7 should `weigh from 19 to 2l grams and m'aybe pressed either loose orv in pellet form, on top of the Thermit charge 7 under a dead load of 6,000'to 7,000 lbs. using a ram shaped to form the rounded depression' 111 One type of first fire charge 9 which has beenfound'to be satisfactory comprises 25% magnesium' powder and 75% barium chromate.'

lAs indicatedV above, the' toxiclincendiary bomb 5 is particularly' adapted to beV dropped from bombing aircraft. In operation, when a cluster of the bombs is dropped" on a target from an aircraft, the bands which hold the bombs '5 in the cluster are broken so as to permit the individualb'ombs 5 to fall separately in a pattern on theltar'get.' As the clustered bombs 5 separate from. each other, the safety pins 31 are released to the position shown in Figures 1 and 3 so as to ypermit the downward fall ofthe firing pin 18. Upon impact of the noses of'a bomb l5, the inertia ofthe firing pin 18 acts to deform the retainingvcross-shaped member 26 so as to allow the point 22 of the firing pin 18 to strike the primer cap 1'5. The primer cap 15 flashes into the depression 11'of the first re charge 9 so asfto ignite the same. The gaseous products of combustion from the ignition of the iirstfire charge 9 are suicient to blow out the vent hole plugs 34 and thus prevent the explosion of the bomb 5. Y

The rst fire charge 9burns at a temperaturesufficient- 1y high to ignite the Thermit charge 7 which in turn ignites the magnesium-cadmium casting V6. An intense incendiary action is obtained; and upon burning of the casting 6, a cadmium oxidev smoke or aerosol tis formed which is extremely toxic. Thus, in order'for the bomb 5 to be safely extinguished, the firefighter must Wear a gas mask having a filter which will give protection against the cadmium oxide aerosol.

Referring to Figures 4, 5 and 6 of the drawings, a modified form of toxic incendiary bomb is indicated generally at 40 which comprises a cylindricallyV shaped iron casing 41 loaded with a cadmium-containing lThermit-type charge 42. The preferred form of the bomb 40 has a weight of 4 lbs. and an over-all length`off2l1152 inches, thereby making it of the same weightA and-cdimensions as the preferred form ofthe bomb 5V of FigureV 1. The lower orleft hand end ofthe bomb V40'is'provided with a hexagonally-shaped cast iron nose'43 so as toY maintain VtheV bomb --40 Vinupright positionduring ight. The cha`rge=42` maycomprise a;Thermit'composition of the type used'for the Thermit'- charge 7 in the bomb 5, s

Figurey 1, having mixed'unformly therewith powdered cadmium metal. `The cadmiumV metal may comprise 20% of the weight of the charge 42.

The charge 42 is'loaded into the casing 41 in a man-vv ner similarto that-described above iny connection with that of the first fire charge 9 of the bomb -5 -of Figure l.

The first lire charge 44 isv adapted to be ignited by `a primer cap'46h'eld in a'primer cap holder 47ttir'1g Vin theV lowerorleft' hand -end of a firingY pin Aasserr'ibly 481r ,The tiring pin assembly 48v is heldin position in' the upper or -righthand' end ofthe casing 41-by six screws 49as primer cap 46, a firing pin 52 is provided in a firing pin holder 53 preferably formed of aluminum. The tiring pin 52 is normally spaced away from the primer cap 46 by'means of a compression spring 54. A safety pin 55 is provided for the firing pini 52 as-shown in Figures 4 and 6 which corresponds to the safety pin 31 shown in Figures l and 3 for the bomb 5 described in connection therewith. A hexagonally shapedk sheet steel tail 56' is A1 fastened over the firing pin assembly 48 by means of screws'57 as shown in Figure 4.

In order to prevent the gaseous products of combustion of thefirst fire charge 44 'and the incendiary charge 42 from exploding the bomb 40 and extinguishing the burn` ing incendiary, a number of vent'holes 60 are provided in theicasing 41 between the Vfiring pin 46 Vand vthe first fire chargeV 44, as shown in Figure 4. The holes 60 are closed byfwat'erproof tape 61.

It"vvill be obvious that Vthe 'bomb 40 functions in substantially'the same manner' as the bomb 5 described' The cadmium-containing Thermit charge 42 upon burningsets'offfan intense temperature, and the powered cadmium metal content thereof burns to form a toxic areosol.

In the event` that it is desired to convert incendiary bombs on hand ofthe type shown in Figures l and 4, but wherein lthe body 6 of bomb 5, Figure l, doesv not contain cadmium andthe incendiary charge 42 of the bomb 40l of Figure 4 also does not contain cadmium metal, thisV may be readily done as follows: holes may be drilled into the bombs 5 and 40 and filled withpowdered cadmiumV metal, cadimum Wire or solid cadmium castings. In the case of bomb 5, Figure l, the cadmium may be inserted entirely in holes drilled in the casting 6 or in holes drilled in theThermit charge 7, Vor in both. Such holes for the cadmium deposit may be drilled either in a longitudinal direction into the bomb 5 or crosswise therethrough. In the case of an incendiary of the type 40 shown in Figure 4, the cadmium will be deposited in holes drilled longitudinally or crosswise into the incendiary filling 42.

'Since certain further changes may be made Yin the foregoing constructions, and different embodimentsA of the invention may be 'made without departing from the scope thereof, it is intended that all matter described hereinbefore shall be interpreted as illustrative and not ina limiting sense.

We claim:

1.,'A toxic incendiary munition comprising, in combination, a body formed of a magnesium-cadmium alloyA of the Vfollowing 'percent composition:

arT-herrmit-type charge within saidbodfy, a first Afire charge for igniting said Thermit char-ge,r and firing means for setting off said first frefcharge.- l Y Y @2.3105 toxic incendiary munition .comprising in combinationga body formed of a magnesium-cadmium alloy ofthe followingpercent.composition: Y Y

A1urvninu1af f 6.3%.

Cadmium' 22.5%. zine 1 Lessthan 0.1%. Manganese Y0.22%'. Magnesium 71.4%.

a'Iliermit-'typ'e char-'ge within said body, lalir'st'freA4 charge-- forigiiiting' said ThermitYV charge,- and firing means for setting o said firstffre charge.

3. A toxic incendiary bomb comprising, in combination, a body weighing about 1.4 lbs. formed of a magnesium-cadmium alloy having the following percent composition:

a Thermit type charge within said body weighing about 265 grams, a iirst re charge for igniting said Thermit charge and weighing from 19 to 21 grams, and firing means for setting 0E said first re charge upon impact of said bomb.

References Cited in the le of this patent UNITED STATES PATENTS Vautin Sept. 16, 1919 Ranken Nov. 1, 1921 Hammond Nov. 21, 1922 Gann July 26, 1938 Helmbold May 11, 1943 Epler et al. Feb. 26, 1952 FOREIGN PATENTS Great Britain Aug. 19, 1938 

1. A TOXIC INCENDIARY MUNITION COMPRISING, IN COMBINATION, A BODY FORMED OF A MAGNESIUM-CADMIUM ALLOY OF THE FOLLOWING PERCENT COMPOSITION: 